The present invention relates to bait stations for controlling unwanted pests, such as termites. More specifically, it relates to bait stations that (i) permit one to monitor feeding progress, and (ii) to vary the capacity of the station once feeding has begun, with minimum adverse effect on the feeding as a result thereof.
In many areas of the world homes and businesses experience pest infestations such as termite infestations and other crawling insect infestations. Termites not only nest in buildings, they also tend to destroy those buildings over time as they feed on wood.
Controlling termites in buildings can be difficult as termites tend to burrow deep into wood structures. Hence, merely placing a toxic bait at a random position in a room would normally be ineffective in controlling termites, particularly if the toxic material is fast acting. In this regard, termites may find the entire wood structure of the building to be an equally desirable “bait”, and thus may not be significantly influenced by yet another randomly positioned cellulose source (especially if it is not convenient to their normal path of travel). Further, even if a particular termite happens to feed on a toxic bait, that may do little to control the remaining population if the termite dies quickly near the bait.
One approach for controlling termites that has had some success takes advantage of the fact that termites often repetitively travel along a given preferred pathway, and the fact that termites often ingest the food, and then later regurgitate it along that pathway or at their nest. Hence, a bait can be positioned along a frequently used termite “trail”, and be provided with a slower acting toxicant. “Termite trail” is used to refer to both enclosed termite tunnels and also at least partially open trails.
Positioning of a bait station adjacent a trail, which may be visible along a stucco wall for example, improves the likelihood that the termite will choose to feed at a bait station. Further, the use of the slower acting toxicant helps insure that termites that feed at the station will not immediately be killed at the station. Rather, there will be enough time for the termite to return to the nest and/or trail and regurgitate at those sites. Then, other termites will be likely to encounter the regurgitated bait and feed on it.
A complicating factor in designing bait stations that use this approach is that termites tend to avoid light and also prefer relatively constant environmental conditions (e.g. temperature; humidity) when feeding. When they are faced with a sudden light source, or an altered environmental condition, they scatter to a known safer place. This can be particularly problematic when one wants to check a bait station to determine if the bait has been used up or if alternatively no termites have been attracted.
In U.S. Pat. Nos. 6,058,646 and 6,079,151 there was disclosed a termite bait station in the form of a box-like housing that was positioned against selected walls or floors. The bottom of the housing had an entry positionable adjacent a termite trail. The interior of the housing contained an edible toxic material for controlling the termites. A removable cover was provided to allow for inspection of the housing interior and/or assembly of a second stacked housing.
However, upon removal of the exterior cover, the interior of the housing and associated bait would be exposed to ambient conditions. Thus, even if the cover were removed in extremely low light conditions, termites feeding inside the housing could be “spooked” by a rush of fresh or different temperature or humidity air caused by the cover removal. Thus, inspecting the cavity interior to see if the station was working, and/or whether the bait was completely consumed, could disrupt the function of the station.
As such it can be seen that a need still exists for improved bait stations, particularly those stations that allow for monitoring of the station and expanding of its capacity, both without significantly adversely affecting on-going feeding.